truncate numbers

cat numbers | perl -n -e '$length = 6; my $new_num ; @a = split //; for (0 .. $length - 1) { $new_num .= @a[$_]; } $decimals = $#a - $length -1; $roun= $new_num .= 0 for 0 .. $decimals; print $new_num . "\n"'